1. Field of the Invention
The present invention relates generally to the field of semiconductor packaging, and more particularly to a wafer level package (WLP) having stress-relief features embedded in an upper portion of the molding compound.
2. Description of the Prior Art
Wafer level packaging process is known in the art. In a wafer level packaging process, a wafer with integrated circuit fabricated therein or chips mounted thereon undergoes a series process, such as grinding, die-bonding, molding and so on, and is finally cut into finished products. Wafer level packaging process has been considered as suitable technology for small sized and high-speed package.
In wafer level packaging, the wafer and the dies mounted on the wafer are typically covered with a relatively thick layer of the molding compound. The thick layer of the molding compound results in increased warping of the packaging due to coefficient of thermal expansion (CTE) mismatch, and the thickness of the packaging. It is known that wafer warpage continues to be a concern.
Warpage can prevent successful assembly of a die-to-wafer stack because of the inability to maintain the coupling of the die and wafer. Warpage issue is serious especially in a large sized wafer, and has raised an obstacle to a wafer level semiconductor packaging process. Therefore, there remains a need in the art for an improved method of manufacturing wafer level packages.